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PubMedDate not supplied

[Age-period-cohort analysis of mortality caused by traffic accidents in Spain].

OBJECTIVE: To study the evolution of traffic accidents mortality in Spain and its possible application to an age-period-cohort analysis, as well as the effect of selected road safety measures. MATERIAL AND METHODS: Road accidents rates of mortality were obtained, and five-year interval age rates for each sex, which allows the study of specific rates of age by birth cohorts. To determine the association between the selected road safety measures and mortality. Poisson regression models were adjusted. RESULTS: Two waves emerge in the evolution of traffic accidents. There was no clear effect with respect to age, nor was there a cohort effect for men or women. As to the road safety measures, we discuss the consistency between the selected models and graphic results. The compulsory use of helmet and of crossing lights is significantly associated to a reduction in mortality (RR 0.73, p < 0.05). CONCLUSIONS: Road accidents mortality shows a slight increase in the studies period. This rate performance cannot be sufficiently explained by age effects, diagnostic period nor birth cohort, however, road safety measures are considered positive.

Accidents, Traffic↗
PubMedDate not supplied

[Age-period-cohort analysis of mortality caused by ischemic cardiopathy in Spain 1965-1985].

With the objective of studying the temporal evolution of ischaemic cardiopathy (IC), or coronary heart disease mortality, in Spain, we carried out a cohort analysis with conventional graphic techniques and modern statistical methods. This permits better understanding and quantification of the age-period-cohort effects and identification of the potential factors operating upon them. To this end, loglineal (Poisson regression) models were constructed of the IC mortality rates for both sexes, using the GLIM package, in which the regression coefficients are the natural Relative Risk (RR) logarithms of the various age groups (35-74 years), period of death (1970-1985) and birth cohort (1985-1960) with respect to the reference group mortality, controlled by the effect of other groups. In respect of the results, the maximum RR value corresponds to decrease year 1975, and falls progressively to 1985, though at all times remaining above the 1970 value. The effect of 1985, though less than 1980, does not present significant differences from the latter. Nevertheless, no clear cohort effect was found. As a probable explanation for the pattern observed, this would suggest recent changes in life style and in medical attention. There is a discussion of the consistency of the models selected with the graphical results and with present knowledge of the natural history of IC and with the evolution of its determining factors, together with validation of the models. In summary, the IC mortality patterns observed show an increase up to the mid-seventies, and stabilization from that date onwards, in all age and sex groups, which is consistent with an age-period effect.

Adult↗
PubMed1993

A birth cohort analysis of the smoking epidemic in West Germany.

STUDY OBJECTIVE: The aim was to provide insights in the spread of the smoking epidemic and eventual progress against cigarette smoking in West Germany. DESIGN: This was a retrospective birth cohort analysis based on a cross sectional national survey. SETTING: The survey was conducted in 1987 by the Ministry of Youth, Family and Health in order to identify priorities for health policy and promotion. The target population were all residents of German nationality above the age of 14 years. STUDY POPULATION: 1721 men and women of the birth cohorts 1911-20, 1921-30, 1931-40, 1941-50, 1951-60, and 1961-70 were included in this analysis (65.7% overall response rate). MEASUREMENTS AND MAIN RESULTS: The participants were asked for their detailed life time history of cigarette smoking in a personal interview. This information was used to calculate and plot historical smoker prevalences by sex, level of school education, birth cohort, and calendar year after correcting for differential survival of smokers and non-smokers. In men, smoking prevalences increased slowly from birth cohort to birth cohort and reached a maximum of more than 70% in the 1941-50 cohort in the early 1970s. While smoker prevalences were considerably lower in the two youngest birth cohorts among better educated men, no major changes were observed in men with lower educational status. The rise of the smoking epidemic in women seems to have levelled off only very recently. CONCLUSIONS: In contrast to other countries with more powerful antismoking campaigns, no major progress in the fight against cigarette smoking has so far been made in West Germany. Major public health efforts are badly needed to limit the epidemic of smoking attributable diseases in this country.

Adolescent↗
PubMed2004

Increasing risk of gastroschisis in Norway: an age-period-cohort analysis.

The prevalence of gastroschisis in Norway, as reported to the Medical Birth Registry of Norway, increased regularly and sixfold from 0.5 to 2.9 per 10,000 births during 1967-1998. The prevalence was also consistently higher among children of younger mothers. The authors used age-period-cohort analysis to assess effects of both parents' age and year of birth (parental cohorts). Mother's and father's age were included in three different regression models. Apart from a significantly higher risk at a young maternal age, the authors also found higher risk at a young paternal age (1.6-fold per 10 years' reduction in father's age, 95% confidence interval: 1.0, 2.4). The time trend was highly significant regardless of whether it was ascribed to period, mother's year of birth, or father's year of birth. However, when father's year of birth was used to describe the time trend, no apparent additional effect of father's age was found, only for mother's age. The time trend is likely caused by environmental factors. Persistently increasing risks among children of young mothers may hypothetically be related to lifestyle factors. A contribution to risk also from fathers born in more recent years or from young fathers increases the likelihood that a factor related to modern lifestyles of young couples may be related to risk.

Adult↗
PubMed1996

Age-period-cohort analysis of the incidence of schizophrenia in Scotland.

Studies examining a possible decline in the incidence of schizophrenia over the last two to three decades have paid little attention to the possible role of birth cohort effects. We collected data on a Scottish national sample of all schizophrenic patients, admitted for the first time between 1966 and 1990 (N = 11348; male = 6301). In an Age-Period-Cohort analysis, a full model, incorporating three factors, had a substantially better fit to the data than other models (especially, an Age-Period model), providing clear evidence of the presence of a cohort effect. After adjustment for the effects of age and period, there was a 55% reduction in the rate of schizophrenia in men and a 39% fall in the number of women over the 50-year birth period from 1923 to 1973. The marked decline in the first admission rates observed in Scotland cannot, however, be attributed entirely to this cohort effect. Rather, a greater proportion of the declining first admission rates (88%) is ascribed to the period effect (i.e. artefactual or causally related cross-sectional effects). Nevertheless, the fact that a birth-cohort effect accounts for part of the declining incidence, suggests that causal environmental factors operating early in life have been diminishing in intensity.

Adolescent↗
PubMed1985

Birth-cohort analysis of peptic ulcer mortality in Europe.

The age- and sex-specific death rates of gastric and duodenal ulcer are followed in eight European countries over a period ranging from 30 to 60 yr. A cohort analysis demonstrates that the temporal changes of peptic ulcer mortality in the European countries seem to occur in a fashion characteristic of those due to changes in birth-cohort risks. Generations born at the end of the 19th century manifested a high risk of dying from gastric and duodenal ulcer. The birth-cohorts with a high risk for duodenal ulcer lagged 10-30 yr behind those with a high risk for gastric ulcer. Male and female cohorts with the highest risk were born at the same time. The birth-cohort phenomenon is most obvious in male death rates of gastric and duodenal ulcer. A birth-cohort phenomenon would imply that important determinants for the development of gastric and duodenal ulcer occur early in the life of a cohort and that it is these early determinants that are changing with time. The determinants could be environmental factors which interact with the pathophysiology of peptic ulcer from the outside.

Adult↗
PubMed1993

The epidemiology of peptic ulcer mortality 1953-1989: a birth cohort analysis.

Peptic ulcer (PU) disease is the cause of substantial morbidity and mortality in a number of countries including Australia. Despite diagnostic and treatment advances, sustained mortality from PU disease has been reported. To understand this problem a birth cohort analysis using the Median Polish Technique (MPT) was performed on 36 years of mortality data from New South Wales, Australia. The MPT allows cohort effects to be quantified, yet has rarely been applied to mortality data. Birth cohort effects detected using graphical presentation of mortality data for duodenal (DU) and gastric ulcer (GU) mortality data for both males and females, were supported by the results obtained using the MPT. The DU mortality rates for females increased significantly over the 36-year period. This increase can be explained by the presence of a birth cohort effect, with women born between 1898 and 1913 having a greater risk of dying from DU than preceding or subsequent generations. Cohort effects in GU and DU mortality data for males and in GU mortality for females were also present, although these were masked by the overall decline in PU mortality rates. The results support the findings of other studies of birth cohort effects in PU mortality data from England, Europe and Japan, and provide support for the existence of environmental factors which resulted in increased PU mortality among specific birth cohorts. Demonstration of these birth cohort effects should influence the theories of PU disease aetiology and prevention and should be considered in developing approaches for further research.

Aged↗
PubMed1994

Fluvastatin in familial hypercholesterolemia: a cohort analysis of the response to combination treatment.

A recent randomized, double-blind, double-dummy trial revealed differences in the response of patients with heterozygous familial hypercholesterolemia to combination therapy with the new, wholly synthetic 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor fluvastatin, 20 mg/day and then 40 mg/day, plus the fibric acid analogue bezafibrate, 400 mg/day, vs combination therapy with fluvastatin, 40 mg/day, plus the bile acid sequestrant (resin) cholestyramine, 8 g/day. The main purpose of the present cohort analysis was to determine whether these differences in lipid response were related to imbalances in the patients' prior responses to up to 42 weeks of fluvastatin monotherapy, 20 mg/day, 40 mg/day, and, in some patients, 60 mg/day, in 2 earlier studies. For the present analysis, we identified 18 patients in the fluvastatin plus bezafibrate group (cohort 1) and 16 patients in the fluvastatin plus cholestyramine group (cohort 2) for whom complete dose-response data were available for the full 56-week duration of all 3 studies. Subsets of 7 patients in cohort 1 and 8 patients in cohort 2 had received the 60 mg/day fluvastatin dose during a previous monotherapy study. In cohort 1, low density lipoprotein cholesterol (LDL-C) decreased by 19% with 20 mg/day fluvastatin, by 27% with 40 mg/day fluvastatin, by 31% with 20 mg/day fluvastatin plus bezafibrate, and by 35% with 40 mg/day fluvastatin plus bezafibrate, and the LDL-C/high density lipoprotein cholesterol (HDL-C) ratio had fallen by 46% at the end of combination therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Birth cohort analysis of prevalence of cigarette smoking among Hispanics in the United States.

To investigate historical trends of cigarette smoking among Mexican-Americans, Cuban-Americans, and Puerto Rican-Americans, we conducted a birth cohort analysis of smoking prevalence by using smoking histories of 8286 adults and adolescents from the 1982-1983 Hispanic Health and Nutrition Examination Survey. We constructed smoking prevalence curves for men and women among successive ten-year birth cohorts. Birth cohort-specific prevalence rates were higher for men than for women. Rates, however, decreased among successive cohorts of men. Conversely, rates increased among successive cohorts of Cuban-American and Puerto Rican-American women. For example, peak rates among the 1911 through 1920 cohorts were 26% (Cuban-American women) and 25% (Puerto Rican-American women) compared with peak rates of 43% and 52%, respectively, among comparable groups from 1951 through 1960. These results demonstrate that despite a reduction of cigarette smoking among successive cohorts of Hispanic men, Hispanic women have made little progress or have actually increased their cigarette smoking.

Adolescent↗
PubMed1997

Understanding and enhancing compliance with the second dose of hepatitis B vaccine: a cohort analysis and a randomized controlled trial.

OBJECTIVE: To determine the predictors and extent of noncompliance with a second dose of hepatitis B vaccine and the effectiveness of a compliance enhancement strategy. DESIGN: Cohort analysis and randomized clinical trial. SUBJECTS: A total of 256 consecutive adults attending a sexually transmitted diseases clinic from October 1992 to July 1993 who were seronegative for hepatitis B virus and agreed to receive hepatitis B vaccination. SETTING: Hamilton, Ont. INTERVENTION: Subjects were followed up for 4 months. Those who did not return for the second dose of vaccine by 6 weeks after the first (2 weeks overdue) were randomly assigned to the enhanced intervention group (telephone and mail reminders) or the regular intervention group (mail reminder only). Subjects were considered noncompliant if they did not return for the second dose by 4 months after the first. RESULTS: The risk of not returning for the second dose of vaccine within 4 months after the first was strongly and linearly associated with level of education (p = 0.004). The noncompliance rate among those with less than a grade 10 education was 50%, grade 10-13 education 34%, some college education 15% and some university education 9%. In the randomized controlled trial the enhanced intervention group had twice the compliance rate of the regular intervention group (48% v. 25%; p = 0.008). Subjects with no postsecondary education were highly responsive to the enhanced intervention (relative risk 2.1; p = 0.02) compared with those with a higher level of education (relative risk 1.0; p = 1.0). CONCLUSION: Hepatitis B vaccine recipients with lower educational levels are at increased risk of noncompliance with the second dose of vaccine but are highly responsive to telephone reminders.

Adult↗
PubMed2004

Twin deliveries in the United States over three decades: an age-period-cohort analysis.

OBJECTIVE: Time is an important variable in understanding the recent increase in twin deliveries in the United States. Therefore, this study was designed to estimate the influences of maternal age, period (year) of delivery, and maternal-birth-year cohort on trends in rates of twin deliveries. METHODS: United States natality data were used to assess trends in twin pregnancies resulting in live births. This age-period-cohort analysis included 7, 5-year maternal-age groups (15-19 through 45-49 years), 6 twin delivery periods (1975, 1980, 1985, 1990, 1995, and 2000), and 12, 5-year maternal birth cohorts (1926-1930 through 1981-1985). The independent effects of maternal age, twin delivery period, and maternal birth cohort on twin delivery rates for blacks and whites were modeled using Poisson regression techniques. RESULTS: Our study assessed 95,042 blacks and 401,989 whites with twin deliveries. Twin deliveries increased by 46% for blacks and 62% for whites from 1975 to 2000, with the largest increase occurring in the year 2000. For blacks, maternal age had the strongest impact on the increasing twin delivery rates, followed by period of delivery. For whites, the greatest effect was due to period of delivery, followed by maternal birth year cohort and, lastly, maternal age. CONCLUSION: Our data confirm the importance of nature's biologic contribution of maternal aging to twin delivery rates, but suggest that recent changes in the environment surrounding pregnancy (nurture) also influence twin delivery rates. The relative contributions of biologic versus environmental influences appear to differ among blacks and whites.

Adolescent↗
PubMed2000

Case-cohort analysis of brain cancer and leukemia in electric utility workers using a refined magnetic field job-exposure matrix.

BACKGROUND: The potential association between occupational electric and magnetic field exposure and cancer is well documented in the literature, but there is uncertainty regarding a causal relation. METHODS: Using data from a completed cohort study, we sought to refine the job-exposure matrix in a case-cohort analysis by regrouping jobs into more homogeneous groups, but without making additional measurements. From the original cohort, we selected the 164 men who died of leukemia, 145 men who died of brain cancer, and a random subcohort of 800 men (0.6% of the cohort). Erroneous job assignments were corrected and job groups were subdivided based on differences in work environments or tasks performed. RESULTS: Magnetic field exposure remained unrelated to leukemia mortality and positively associated with brain cancer mortality based on both cumulative and average magnetic field indices. Although not monotonic across the middle intervals, increased risk of brain cancer was found in relation to career exposure, with risk ratios of 1.8 (95% CI = 0.7-4.7) and 2.5 (95% CI = 1.0-6.3) in the uppermost categories for cumulative and average exposure, stronger for exposure 2-10 years past. CONCLUSIONS: Improvements in exposure assignment based only on reassignment of job titles to occupational categories had little impact on the measured associations of magnetic fields with leukemia or brain cancer.

Brain Neoplasms↗
PubMed1995

Value and quality of perinatal and infant postmortem examinations: cohort analysis of 400 consecutive deaths.

OBJECTIVES: To evaluate the contribution that perinatal and infant necropsy makes to clinical practice and to see how this might be influenced by the quality of the investigation. DESIGN: Cohort analysis, with data from the all Wales perinatal survey, of perinatal and infant deaths during 1993 of babies born to mothers usually resident in Wales. The clinicopathological classification of death based on clinical details was compared with the classification after necropsy. Similarly, cases in which necropsy yielded new information were identified. The quality of the necropsy was assessed by scoring six aspects of the examination. SUBJECTS: 400 consecutive deaths at 20 weeks of gestation to 1 year of age. MAIN OUTCOME MEASURES: Necropsy rate, effect of necropsy on clinicopathological classification, new information disclosed by necropsy, quality of necropsies, and the link between new information and quality of the necropsy. RESULTS: Necropsy was performed in 232 cases (58%). The clinicopathological classification was altered by necropsy in 29 cases (13%). New information was obtained in 60 cases (26%), and in 42 (18%) it disclosed the cause of death. The quality of necropsy was substantially higher when the main cause of death was detected than when nothing new was found. CONCLUSION: Necropsy is underused. Clinicians should be more positive about necropsies and realise how much clinically relevant information can be obtained from a good quality examination.

Autopsy↗
PubMed2006

Statins and sepsis in patients with cardiovascular disease: a population-based cohort analysis.

BACKGROUND: Atherosclerosis and sepsis share several pathophysiological similarities, including immune dysregulation, increased thrombogenesis, and systemic inflammation. The relation between statins and risk of sepsis in patients with atherosclerosis is unknown. METHODS: We did a population-based cohort analysis through linked administrative databases in Ontario, Canada, with accrual from 1997 to 2002. We identified 141,487 patients older than 65 years who had been hospitalised for an acute coronary syndrome, ischaemic stroke, or revascularisation, who survived for at least 3 months after discharge. 46,662 (33%) were prescribed a statin within 90 days of discharge, 94,825 (67%) were not. Propensity-based matching, which accounted for each individual's likelihood of receiving a statin, yielded a cohort of 69,168 patients, of whom half (34,584) received a statin and half (34,584) did not. FINDINGS: Incidence of sepsis was lower in patients receiving statins than in controls (71.2 vs 88.0 events per 10,000 person-years; hazard ratio [HR] 0.81; 95% CI 0.72-0.91). Adjustment for demographic characteristics, sepsis risk factors, comorbidities, and health-care use gave similar results (HR 0.81; 95% CI 0.72-0.90). The protective association between statins and sepsis persisted in high-risk subgroups, including patients with diabetes mellitus, chronic renal failure, or a history of infections. Significant reductions in severe sepsis (HR 0.83; 95% CI 0.70-0.97) and fatal sepsis (0.75; 0.61-0.93) were also observed. No benefit was noted with non-statin lipid-lowering agents (0.95; 0.75-1.22). IMPLICATIONS: Use of statins in patients with atherosclerosis is associated with a reduced risk of subsequent sepsis. Randomised trials of statins for prevention of sepsis are warranted.

Aged↗
PubMed1984

Prediction of male lung cancer mortality in Japan based on birth cohort analysis.

The future trend in male lung cancer mortality in Japan was predicted by using a simulation model. The model was based on the age-specific death rates from lung cancer in males by birth cohort, expressed as Fi(t) = rkSitr-1 exp(-ktr). The parameters in the function were obtained from the mortality data in Vital Statistics (1960-1980). The chi-square test for goodness-of-fit supported the statistical validity and acceptability of the function. Extrapolation of the function provided future age-specific death rates by birth cohort for males in Japan. In this simulation model it was possible to evaluate the effects of preventive strategies and/or therapeutic improvements on lung cancer mortality when five additional parameters were taken into consideration. According to this model, the age-adjusted death rate from lung cancer in Japanese males is predicted to increase linearly until the year 2000 and to level off thereafter. The total number of deaths from lung cancer for all Japanese males is predicted to be 27,000 in 1990 and over 40,000 in 2000. With the establishment of an effective preventive strategy for young generations, the mortality would begin to decrease a few decades later. Improvements in the therapy of lung cancer, if realized, might suppress the future upward mortality trend in Japan to some extent. The above simulation model based on birth cohort analysis should be useful in estimating the impact of developments in prevention and treatment of lung cancer as well as in predicting the future mortality trend.

Adult↗
PubMed2001

Case-cohort analysis of agricultural pesticide applications near maternal residence and selected causes of fetal death.

The potential association between fetal death and residential proximity to agricultural pesticide applications was examined in 10 California counties for 1984. A case-cohort analysis utilized 319 cases of selected causes of fetal death other than congenital anomalies and 611 non-cases. A statewide database of all applications of restricted pesticides was linked to maternal address; residential proximity within 1 mile (1.6 km) provided a surrogate for daily exposure. Pesticides were grouped by chemical class and mechanism of acetylcholinesterase inhibition. Multivariate proportional hazards models using time-dependent exposure variables were fit for each pesticide grouping. Overall, pesticides showed no strong association with fetal death. Slightly elevated risks were observed for women who resided near applications of halogenated hydrocarbons, carbamates, estrogenic pesticides, and carbamate acetylcholinesterase inhibitors during the second trimester, with hazard ratios of 1.3 (95% confidence interval (CI): 1.0, 1.8), 1.3 (95% CI: 1.0, 1.8), 1.4 (95% CI: 0.8, 2.5), and 1.3 (95% CI: 1.0, 1.8), respectively. In a month-by-month analysis, elevated risks were observed when exposure occurred during gestational months 3 and 4 for carbamates and carbamate inhibitors and during months 4 and 5 for halogenated hydrocarbons. Since previous studies have relied on personal recall of exposure, major strengths of this study were the objective source for environmental pesticide exposure assessment and the use of data on the timing of exposure.

California↗
PubMed1997

Secular trend and age-period-cohort analysis of prostate cancer mortality in Taiwan.

PURPOSE: We evaluated the secular mortality trend of prostate cancer in Taiwan from 1964 through 1994. MATERIALS AND METHODS: Analyses were based on vital statistics. Relative risks associated with each of the age, period and cohort effects on secular mortality were estimated from a log-linear Poisson model. RESULTS: Age adjusted mortality rates increased more than 2-fold during the last 30 years in Taiwan. Age-period-cohort analysis showed that the age effect was the strongest. CONCLUSIONS: Factors related to aging are the main reason for the increase in prostate cancer mortality in Taiwan during the least 3 decades.

Adult↗
PubMed2005

Age-period-cohort analysis of Swiss suicide data, 1881-2000.

At the end of the 19(th) century, male suicide rates in Switzerland were as high as the respective rates in recent decades, whereas female suicide rates were distinctly lower. An age-period-cohort analysis was performed to provide more information about the gender-specific changes over the last century. Suicide mortality has been reported in Switzerland since 1876 when the standardised registration of mortality data began. The analysed data cover the period 1881-2000. The statistical analyses were based on log-linear models and data aggregated by 10-year age-intervals and 10-year period intervals. The results indicate similar age and period effects in males and females. The estimates representing age-specific risk increase steadily with age, with intermediate plateaus in the 20s and the 50s. The period-specific estimates follow the economic cycles. The birth cohort effects are stronger in males and weaker in females. In the males' estimates, there is a peak in cohorts born around 1840 and a low in cohorts born some 60-100 years later. The estimates increased again in generations born after World War II. In females, the birth cohort estimates are low in cohorts born in the first half of the 19(th) century and increase until the first half of the 20(th) century. Birth cohort effects remain an intriguing topic in epidemiology of suicide. A better understanding of birth cohort effects might open new doors to suicide prevention.

Age Distribution↗